R. Savage, J. Oberling, E. Merilh

Work performed on 4/9/2015.

Summary

We are investigating the channels in the PSL MEDM screens to determine what they do and if they do it correctly, and making changes when needed.  We started with the LO MON on the PSL FSS MEDM screen.  It is a monitor of the LO signal used in the PDH locking of the FSS servo.  We found the gain to be set incorrectly to -0.00666, so we changed it to 0.0044033.  We also changed the readout so that it will read 100% when the LO signal is equal to its nominal value (13.86V), >100% when larger and <100% when smaller.

Details

We have begun an effort to go through the more vaguely labeled outputs on the PSL MEDM screens to figure out what exactly they do and if they are doing it right, and making changes when necessary.  We are starting with the FSS, as that is the hot item in PSL land at the moment, with the LO MON readout located at the bottom left of the FSS MEDM screen.  This signal is read in percentage, but no indication what it is a percentage of.

Looking at page 1 of the FSS schematic in D040105-B shows the LO Mon as the output LOM from an ADC 10-4 directional coupler.  A portion of the LO signal (used as part of the PDH locking for the FSS servo) is diverted and output so we can monitor the LO signal.  This LOM is read into EPICS and sent to a filter with the simple math of: output = (signal – offset) * gain.

The offset is set to -22710.0 counts and the gain is -0.00666.   As this is a monitor signal and reported as a percentage, it follows that the LO MON is reporting the percent error of the LO signal as compared to some nominal value: % error = ((signal – nominal)/nominal) * 100.  This nominal value is the offset in the filter, 22710.0 counts (or 13.86V).  The gain is then equal to 100 divided by the nominal value, or 100/22710.0 = 0.0044033; the gain was found to be -0.00666, so it seems the LO MON readout on the FSS MEDM screen has been misreporting the % error of the LO signal.  We therefore changed the filter gain to 0.0044033.

Also, as the MEDM screen does not properly indicate that the LO MON is a % error, we turned off the offset in the filter.  The math is now: output = signal * gain = signal * 100/nominal.  With this change the LO MON readout will now read 100% when the LOM signal is equal to the offset, >100% when larger and <100% when smaller.

Elli, Nutsinee, Patrick

The medm overview was frozen with white numbers. Restarted the computer and it came back. Burtrestored PLC1, PLC2 and PLC3 to 3:10 this morning.

Nutsinee, Elli

To take a measurement with the end-station HWS, the green beam cannot be resonant in the arm cavity.  To take a measurement while the IFO is locked in red, this means we want to add a misalignment offset to one of the ALS_X/Y_PZT1/2 drivers to misalign the green beam in the cavity.  Today we are working out what offset is required to do this.

First we looked at the Y arm.  We looked at what offset we need to add to H1:ALS-Y_PZT2_YAW_MISALIGN_BIAS in order to offset the beam enough that green is both not resonant in the arm but the beam yet not so badly aligned that we see evidence of clipping on the HWS camera.  We put -3250 counts in H1:ALS-Y_PZT2_YAW_MISALIGN_BIAS , requested 'misalign' state for H1:ALS-Y_PZT2_MISALIGN_SWITCH and 'sum' state for H1:ALS-Y_PZT2_MISALIGN_TYPE.  We turned off the input to the filter at  H1:ALS-Y_PZT2_YAW_OUTEN.  This gave us a good image of the ETM on the EX HWS.  Changing the MISALIGN_BIAS by +/- 100 counts made the image on the HWS camera noticabally worse.

When we came in this morning the interferometer was unlocked and trying to lock.  We set ISC_LOCK to down and ALS_YARM and ALS_XARM to unlocked.  We have left the guardian in this state.  I have left the ALS-Y_PZT2 driver in it's nominal 'aligned' state (and the BIAS values have not changed).  When we statred the flashes in the y-arm were about 1.2 counts, indicating good alignment.  After 30mins the flashes were down to 0.8 counts, indicating the alignment had gotten worse.  This suggests the hysteresis in misaligning and realigning these PZTs may noticablly effect the green alignment.

We are planning to do the same thing on the x-arm, although we have not yet gotten to a good alignment with bright flashes in H1:ALS-X_TR_A_LF_OUT this morning.  But we have noticed the end-X HWS camera isn't taking images properly, so we are going to diagnose that now.  We will leave the X-arm alignment as we found it this morning.

Jeff/Andres will be going to EX, so we turned the BRS Switch OFF (with help from TJ & Jim W).  We will turn them back ON when incursions are complete probably after Maintenance since we have winds hovering around 20mph already.

Ross Kennedy & Ed Daw

Instructions for acquiring 100kHz bandwidth ASD, cross correlation, and cross spectral density measurements with 100kHz bandwidth.
1. Check that the LVEA SR785 in the LVEA is hooked up to the OMC DCPD whitening preamplifier pick-off (channel A) and the long RG-58 cable back to the REFL 
electronics (channel B). I left it hooked up when we departed, but it might have been disconnected, I guess. Check also that the GPIB and wireless internet box are connected and powered up.
2. On a control room machine, cd to /ligo/home/controls/edaw_work/hfross
3. Do ./SR785broadscan
- this generates a sequence of measurements covering DC-102.5kHz in 16Hz bins. There are four resulting plots, in order, ASD from the OMCDCPD1, ASD from REFLAIRQ90, cross correlation density from both ports (note that this is per Hz over 16Hz bins, so multiply by 16 to obtain cross correlation on the usual 0-1 scale), PHASE of the cross spectrum
between OMCDCPD1 and REFLAIRQ90 (mainly useful to see the noise in the phase disappear at frequencies where there is extensive cross correlation. 
Results appear in the saved_data subdirectory. Text files of data are saved there too for more detailed information on line frequencies.
Let me or ross know if this doesn't work - we can probably help fix it.

Alexa, Sheila. Evan, Daniel Koji

• Angle to length coupling on ETMs.  The first attached screen shot shors that when we exicte ETMX pitch or ETMY yaw with broadband noise from 20-50 Hz, we can see broadband noise in DARM.  If you assume this is a linear coupling, the EMTY PUM yaw control signal explains 15% of the noise at 20 Hz, while ETMX PUM pit explains 37%.  
• DHARD dominates these control signals, so we measured both pit and YAw loops and added more agressive roll offs to the existing ones.  (both of these roll offs are pairs of complex poles, at 12 Hz for PiT and 10 Hz for Yaw, both are in FM9).  The second attached screenshot shows the reduction in the control signal with the new roll offs engaged.The next two screenshots are OLG measurements before the new roll offs were added, for the record.  Of course, another way of addressing this problem would be to adjust the coil balancing.  We haven't really optimized the spot positions on the optics yet, so for now reducing the control signal seems like a better solution. 
• We were able to close OMC refl, AS air and POP beam diverters in full lock.  In the past attempts to close POP and AS beam divereters have broken locks.  
• Evan also measured the MICH to DARM coupling and made a frequency dependent FF fitler. 
• We had two lock losses tonight where the rotation stage seemed to get confused and reduce the power in the increase power state.  A screen shot of the second one of these is attached.
• The other interesting thing about this lock loss was that all quad PUM current watch dogs tripped.  ITMX and ETMX required a coil driver power cycle to reset.  

Unfortunately, all of these promising developments happened during a lock where the ETMY ESD was tripped, untripping it breaks the lock.  Evan has edited the guardian so that it will not move past ALS unles the ESD is on, so this should not happen to us again.  

Sadly, the wind  started gusting to 30-35 mph while we were reseting the PUM watchdogs, and is forecast to stay that way for about 24 hours.  We have locked with these kind of windspeeds before, but today we are having difficulty, perhaps because the ground motion below 1 Hz was not small even before the wind started.  The BRS is on at end X with broad low frequency sensor correction, however this storm seems to be mostly along the Y direction.  Evan has also increased the common tidal bandwidth again (0.08 now).  We've ben keeping ALS locked for 10-15 minutes.  

We finally have a complete set of medm screens for the timing system.

There are a lot of red indicators due to the fact that the svn revision numbers are reported as zeroes by the DuoTone and IRIG-B slaves. There is no indication that we are not running the firmware we think we do, but we can't really check this.

The EX fanout reports a VCXO range error which has been there for a long time and is most likely is due to a busted readback.

All other master, fanouts and slaves are reporting a green status.

J. Kissel, S. Dwyer, E. Hall, K. Arai, K. Izumi

I'm embarrassed to say I'm overwhelmed by the wealth of open loop gain transfer functions (OLGTFs) that have been taken recently. But, there's also a ton of stuff to explain, so I summarize comparisons and information from the 3 OLGTFs that were taken prior to this weekend here. More to come on this past weekend's new data.

Summary Points: 
- With a "streamlined" matlab model (similar in content to, but separate from the Noise Budget DARM loop model) we can predict the following DARM OLGTFs (measured between 5 and 300 [Hz]):
2015-03-10, Prior to DARM Loop Shape Modification LHO aLOG 17153
2015-04-02, Post DARM loop modification LHO aLOG 17642
2015-04-06, Post DCPD Analog Electronics Compensation Correction LHO aLOG 17710
to within 10% in magnitude and 5 [deg] in phase (between 5 and 300 [Hz]), with the following uncertainties (determined by the standard deviation of the model parameters for these three comparisons):
     - DC optical gain of 1.1e6 +/- 8%
     - residual, [unknown / unaccounted for] time delay of 93 +/- 30 [us]
- The DCPD Analog Electronics Compensation confusingly did *not* affect the frequency dependence of the OLGTF between 2015-04-02 and 2015-04-06, even to the 10-20% level Koji suggests. As of now, based on these measurements alone, I argue that the lack of discernible change in the OLGTF suggests that we do *not* need to make any correction to our CAL-CS front end calibration.
- Just because I can model the open loop gain TFs to this uncertainty level does *not* mean the overall DARM calibration has this uncertainty. We still have a (potentially) large variation in ESD actuation coefficient due to charge, a (potentially) large uncertainty in the DARM coupled cavity pole frequency, a (potentially) large optical gain fluctuation from lock to lock, and (potentially) large discrepancy between the real actuation strength and what we've measured, and all things of which we haven't realized.

Detail Points:
--------
- Kiwamu had put together a "simple" model of the DARM loop when he'd updated the DELTA L EXTERNAL calibration in the CAL-CS front-end filters after the second-to-last time the DARM loop shape was changed (see LHO aLOG 17151). As he mentions in his aLOG, this code lives here:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Scripts/DARM_OLTFGTF_LHOaLOG17153.m
That model had included
    Actuation Function
    - The QUAD SS Model that have the current foton filter file's damping filters engaged with gains that are hard-coded into the generate_QUAD_Model_Production function to gather the necessary damped SUS transfer functions in [m/N], i.e. the output of 
    /ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/MatlabTools/QuadModel_Production/generate_QUAD_Model_Production.m
    using the 
    /opt/rtcds/lho/h1/chans/H1SUSETMX.txt
    foton file.
    - An assumed DAC gain of 2^18 / 20 [V/ct].
    - The UIM analog electronics chain using 
    /ligo/svncommon/SusSVN/sus/trunk/Common/MatlabTools/make_OSEM_filter_model.m
    all parameters of which are "as designed" and not measured. This turns the [N] of drive at the UIM into [ct] of drive at the output of the ETMX_L1_LOCK_L bank.
    - The ESD analog electronics chain using a simple, linearized model of 2*alpha*Vbias*40^2, where 40 is the range of the DAC, Vbias is the bias voltage, in units of the DAC [V], and alpha is the force coefficient. He uses the force coefficient that has been confirmed by measurement to be (2.0 * 1.417)e-10 = 2.834e-10 [N/V^2]. (see LHO aLOG 16843) 
    - The ESD driver's single pole filter
    - The correct hierarchical filters from the current foton file (same as above), with known gains grabbed from conlog.
    The DARM filter
    - Loaded in from the H1OMC foton file from the filter archive,
    /opt/rtcds/lho/h1/chans/filter_archive/h1omc/H1OMC_1110098950.txt,
    with known gains from conlog.

    The Sensing Function
    - Assuming the Actuation and DARM DC gains are correct, the remaining scale factor needed to match the OLGTF model to the measurement is what is used for the interferometer's optical gain, in [m/ct]
    - A single-pole zpk filter, with the pole at 389 [Hz]

    Time Delay
    - An overall true time-delay to account for *all* the high frequency behavior like anti-imaging and anti-aliasing filters.

I've used this model as a template to get started, but I've made the following changes to (a) be able to compare many OLGTFs against the model that best represents the DARM loop at that time, and (b) include the now-better-known high-frequency effects:
(1) Pulled out the hard-coded parameters of the model, and put them in a separate function identified by their GPS time,
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Scripts/
H1DARMparams_1109994128.m
H1DARMparams_1111998876.m
H1DARMparams_1112399129.m
(2) I've modified the filter files chosen such that both the OMC *and* the SUS are pulling from the filter archive, not the live data. This will be come relevant later when we track changes in UIM / TST crossover, or when we begin using all stages like LLO has.
(3) I've now included both the analog and digital anti-aliasing in the sensing function, and the analog and digital anti-imaging in the actuation function. The digital AA and AI filters are the same, from the function
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/S7/Common/MatlabTools/iopdownsamplingfilters.m
and the analog AA and AI filters are the same, taken from .mat file inherited from the 40m, which has been pruned and now lives in
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/S7/Common/MatlabTools/analog_65k_AAAI_filter_response.mat

(4) I've included the known time delays:
Sensing: 1 IOP Computation Cycle (65k) + 1 OMC Computation Cycle (16k)
Actuation:1 SUS Computation Cycle (16k) + 3-Cycle IOP Error Checking (65k) + 1 IOP Computation Cycle (65k) + Zero-order Hold Delay (1/2 a 65k cycle)
(which total 205 [us]) and created a new parameter for the "unknown" time delay, which is fit to make the high-frequency phase flat.

Known remaining flaws in the model:
- Mismatch in digital compensation for analog whitening or pre-amps of the DCPDs -- but this should now be *much* better than before (see LHO aLOG 17650)
- Mismatch in digital compensation for analog whitening of the SUS UIM coil driver and now the ETMY ESD Driver filter 
    -- Measurements have shown that the UIM driver agrees quite well with the model (see LHO aLOG 4495), but this hasn't been confirmed for these SUS individually and/or after their increase in range (Integration Issue 762).
    -- The "temporary" ESD low-noise filters (E1500164) were compensated with their designed poles and zeros, I don't know how well they're matched.
- The model uses 389 [Hz] for the DARM coupled-cavity pole, but this is a modelled value from the L1 IFO's losses (see LHO aLOG 15923). Our losses are larger, so we expect our cavity pole frequency to be higher. More to come from Paul and Daniel on this. The data out to 1 [kHz] from over the weekend should also help with getting a measured confirmation.

This model is a function which takes in the parameter files, is called 
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Scripts/H1DARMmodel_preER7.m,
and returns the modelled and measured open loop gain as well as every single possible thing you could possibly ever want out of the model in a parameter structure (including the things that are independently computed in the model itself, like the full actuation function and the full sensing function).
This model can then be looped over, which I've done with the function
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Scripts/CompareDARMOLGTFs.m

I *hope* that this makes it much easier to compare a new DARM OLGTF against others as we take them.

Scott L. Ed P. Chris S.

The crew cleaned 70 meters from last single door to mid station on X-1. Crevice tool cleaning remaining on that section. 

Beam tube pressures monitored by control room operator during cleaning operations.  

Last week I tried exporting some of the blend filters mods that I had developed at ETMX, but found that at least one of the blends didn't work. Today I worked on figuring out why.  I started by doing an ugly hack of Jeff's plot_current_blends script so I could look at the original LLO  blends in complementary form. When I used the hack to look at what I had installed, it became immediately clear why my blend didn't work. In the attached image, I show the complementary version of the "bad" blend (solid lines) and a "good" blend. The good blend is what is currently running on st2 on all of the BSC's in X,Y,Z and RZ. It's a modification of a 250 mhz blend that we stole from LLO (they run a similar blend). The bad blend is a modified version of the 01_28 blend we use on the HAM ISI's. You can see that at .4 hz I managed to introduce a notch ( in the solid red line) that did all kinds of band things to the plant.

This happened because I was designing in foton (blind), and couldn't see the complementarity of the blends from there. I thought I was safe because I was making small adjustments and was trying minimize any phase wobbles around the blend frequency. Turns out that is not enough. I think fixing the complementarity will be relatively simple,  the first image in my alog  17790 shows why I would like to get this to work, roughly an order of magnitude reduction at 1 hz, with some low frequency injection.

The amazing part is this blend runs on ITMY and ETMX.

The 2 attached pdf's are the original blends (1st pdf) and modified blends (2nd pdf) for both stages X, Z, RY, RZ , shown in both installed and complementary versions.

The successful mods I made are adding elliptical filters to the St1 90 mhz Z blend (alog 17702), a more effective elliptical to the St2 250 blends (alog 17488) and an elliptical to 750mhz St1 RZ cps blend. I haven't found the to do much good, but it doesn't do any harm that I've seen.

Kyle, Gerardo 

We switched HAM5/6 annulus pumping over to the small annulus ion pumps and removed the pump carts -> The 500 l/s "main" ion pump was valved into HAM6 but we are leaving the turbo pump pumping in parallel with it over night 


- Commissioners -

HAM6 high voltages components (picomotors, PZT and fast shutter) can be left energized/enabled without monitoring HAM6 pump curve now.

Went through an initial alignment after the PSL incursion, but had issues getting the full interferometer to lock up.  Commissioners had a few attempts which have come close to DC Readout this afternoon, but H1 dropped out at various steps.   They're continuing to get H1 locked UP.

Summary of Day's Activities:

• 8:51:  Jodi to Ymid
• 8:52-9:10:  jeff/andres in Cleaning Area
• 9:10:  fiber work going on in MSR & VPW room
• 9:16 Gerardo heading out to HAM6 for Pump work (switching on Ion Pumps).  Will leave pump cart hooked up until they are happy with Ion Pumps.
• 9:20 Filiberto:  Powering ON Fast Shutter [& Shutter toggle ENABLED] & PZTs in Electonics room
• 9:18 Hugh investigating HAM6 ISI
• 9:28-11:42 Peter/Ed working on FSS ("for an hour")
• 10:30 Jim W trying out L1 Blend Filters on a HAM (~1hr)
• 1:30-2:00:  Gerardo valving out pump cart (and will see if Ion Pumps are happy)
• Dale with big tour after 1pm
• 3:00 Mike/Fred/Richard tour out to the H1 Elec Room

Today, I restored the ITM misaligned TEST_OFFSET and TEST_GAINs which I found to be showing as diffs in SDF - Sheila had been playing with them last week but said they should be restored.  Snapshots of the ITMy "was" and "now" (aka good) values are attached.

Turned ITM R0 OPTICALIGN zeroed offsets and inputs off - these are never used and are just confusing when found on.

Cleaned out BIO/COIL/TEST_SW2 and LOCK_SW2 changes like has been ongoing across all SUSes.

Rolf, Jim, Dave:

after removing the LSC RFM receive errors completely last week, I noticed that the ASC is getting receive errors from the ALS models at the end stations at a very low rate.

The rate of error is one every 8 to 10 hours. The return of the errors can be tracked back to the ALS model changes made last Tuesday 07apr2015 during maintenance. A trend of the ALS CPU usage shows a difference in signature (attached plot shows last 2 weeks of trends) starting last tuesday.

To remind everyone, when the end station ISC was split, the ALS is the "slow" component, so RFM errors would not be entirely unexpected from this sender.

An understanding of beam tube motion as a function of wind speed is important in predicting scattering noise from the beam tube baffles and in deciding if we need to re-insulate the beam tube. This data was taken during the windstorm on Apr. 11, 2015 at baffle #96 (near the power maximum for the diffracted light from the pattern on the original optics), near the first double doors towards the CS from MY. Figure 1 is a photo of the accelerometers attached to the beam tube, and Figures 2-4 show the motion along the different axes at 3 different wind speeds (9, 18 and 24 MPH). As a first guess I would expect peak amplitudes to increase roughly with wind speed to the 3/2 power (wind power goes as the cube), and, very roughly, it seems consistent.

Raw data archive

Today's quest to increase the bandwidth of the FSS involved the following steps:

• removing both notches in the EOM path
• re-installing the original notch of 220 uH and 150 pF
• changing out the 150 pF cap for a 120 pF cap
• restoring the TTFSS back to its original configuration

The file NONOTCH1.TIF is the open loop transfer function with no notches installed.

Unfortunately the NPRO noise eater was oscillating for this measurement.

The file NONOTCH2.TIF is without the NPRO noise eater oscillating.  One can see

the ~760 kHz resonance that the notch was installed for originally.

The file 150PF.TIF is the open loop transfer function with just the one notch installed.

That notching being the one with 220 uH and 150 pF.  The unity gain frequency is a little

over 300 kHz here.

The file 120PF.TIF is the open loop transfer function with the 150 pF capacitor replaced by

a 120 pF capacitor.  The rationale being moving the notch frequency higher might still attenuate

the 760 kHz resonance enough and allow the gain to pushed a little higher.  This introduced

either another resonance or did not sufficiently suppress the 760 kHz one.

The file RESTORE1.TIF shows the open loop transfer function with the TTFSS restored to its

original state.

For all measurements the reference cavity transmission was ~1.45 V, the fast gain was 18 dB

and the common gain was 22 dB.

Ed, Peter